The present invention relates to exit devices, and more particularly to exit devices that are visible in low light or dark conditions.
An exit device is a manual or electronic door operating mechanism operated from the inside of a door. A conventional exit device generally includes a frame or housing secured across a door face and substantially spanning the width of the door. A touch bar is movably mounted to the frame. The touch bar is mechanically linked to a latch mechanism, including a door latch which is movably mounted in the frame adjacent to a free edge of the door. Manually depressing the touch bar in the frame toward the door translates the mechanical linkage for actuating the latch mechanism in order to retract the door latch so that the door can be opened allowing egress.
During low light or dark conditions, such as during a power failure, or in an emergency, it is important to those within the building to quickly identify building exit doors. Commercial buildings are required to have signs identifying exits as well as directional or warning signage, which indicate to building occupants a path for leaving the building in low light or dark conditions. A pathway marking system may include passive lighting, which does not require a power source, to demarcate the outlines or sections of buildings structures such as stair risers, intersections of walls and floor, sloped ramps, doorways, hallways, or the location of handrails, and the like. Some passive pathway marking systems utilize photoluminescent materials which provide low level light as they discharge their stored energy. Photoluminescent materials contain inorganic phosphorus and pigments that absorb ambient light. In darkness, the photoluminescent material produces a sustained visible yellow-green, red or blue glow which provides sufficient illumination for guiding someone out of a darkened area. Examples of photoluminescent materials include zinc sulfide and alkaline metal oxide aluminates, such as calcium sulfide and strontium sulfide.
Unfortunately, passive marking systems have not been applied to exit devices. Electroluminescent exit devices are available. However, an electroluminescent exit device requires electricity with battery back-up power, and includes electrical wiring which extends through the exit device, the door and one of the door hinges for connection to a source of power.
For the foregoing reasons, there is a need for a photoluminescent exit device which is visible in low light or dark conditions for directing an occupant to a point of egress of a room or a building. The new exit device should ideally function effectively as a passive lighting device in a pathway marking